Letters demanding payment on an account I closed years ago.
Photograph: DNY59/Getty Images

I received a letter from a debt collection agency stating that I owed Barclays £849.16. All it could tell me was that this was to do with an account I had closed in 2002.

After further investigation, it seems the account, for which I paid a monthly fee, was never closed and charges continued to accrue for nearly 15 years.

I have a statement showing the account was £10 in credit when I tried to close it. I’ve moved several times since then, but always arranged for post to be forwarded and have never received any communication from Barclays concerning a debt.

The agency advised me to contact the bank, but Barclays staff said that since the account had been closed 14 years ago, it couldn’t help.

I was advised to go into my local branch instead, where it was discovered that because the account had been £10 in credit when I asked to terminate it, the system could not close it down and as a result it continued accruing interest and charges.

When I asked why I had not been informed or contacted, the man said that because I had an overdraft facility of £700, the bank did not get in touch until I had gone over it, which given the amounts involved, took more than 14 years.

Despite being sympathetic, branch staff did not know what to do and suggested I contact the debt collection agency!

Two months on there is still no resolution and the debt has now affected my credit rating. SC, Cambridge

This is a bizarre story, not least the explanation from your local branch which contradicts the response from the Barclays press office.

According to the latter, the account was not £10 in credit, as your last statement suggests, but £31 overdrawn – which is why it was not closed.

This small sum morphed into three-figures because a letter Barclays now claims to have sent you at the time never reached you, and so interest and fees mounted up. Quite why they were allowed to mount for so many years is not explained.

It looks as though the whys and wherefores will remain forever opaque. But the good news is that Barclays has now reclaimed the debt from the collection agency and, although it insists it did not make a mistake, has informed you that it will be written off and removed from your credit record. Nor will it pursue you for the £31 that started this expensive ball rolling.

“It is important for customers to ensure the bank has the correct correspondence address, and to ensure any overdraft balance is brought to zero,” says Barclays. “With mobile banking apps and online banking, it’s very easy to monitor accounts.”

If you need help email Anna Tims at your.problems@observer.co.uk or write to Your Problems, The Observer, Kings Place, 90 York Way, London N1 9GU. Include an address and phone number.